This core maintains our kidney stone patient data base. From the data base, the Core identifies appropriate patients for protocols in Projects 1, 3 and 4. Patients are contacted, and recruited into protocols. Where necessary, the Core establishes informed consent. For protocols involving 24 hour urine samples, the Core obtains the samples. From human urine samples and samples from the IH rats (Project 2, Core A), the Core prepares whole urine proteins and isolated nephrocalcin, Tamm Horsfall protein and Uropontin for use in Projects 2, 3, and 4.